1. Field of the Invention
This invention relates to a liquid crystal display, and more particularly to a liquid crystal display module that is adaptive for improving a ground connection between a printed circuit board and a ground plate.
2. Description of the Related Art
Generally, a liquid crystal display module consists of a liquid crystal panel and a driving circuitry for driving the liquid crystal display panel. The liquid crystal display panel includes liquid crystal cells arranged between two glass substrates in a matrix type, and switching devices for switching signals applied to the liquid crystal cells. Since the liquid crystal display module includes a glass substrate and thus is liable to be damaged due to an external impact, a case for enclosing the outside of the liquid crystal display module to protect the liquid crystal display module has been used in order to prevent a damage of the liquid crystal display module caused by an external impact.
Referring to FIG. 1, a liquid crystal module 1 includes a liquid crystal display panel 80, a frame 82 made from a plastic material, and a top case 2 engaged to the frame 82 to enclose the edge of the liquid crystal display module 1.
The liquid crystal panel 80 has a printed circuit board (PCB) 4 mounted with a driving circuitry (not shown). The plastic frame 82 is provided with a lamp for a backlight (not shown), a light guide and sheets for light reflection, diffusion and focusing, etc.
The liquid crystal display panel 80 is inserted into latches (not shown) provided at the front side corner of the plastic frame 82 to fix it to the plastic frame 82. At this time, the PCB 4 is folded in such a manner to enclose the rear side of the plastic frame 82 to be positioned at the upper rear side of the plastic frame 82. The plastic frame fixed with the liquid crystal display panel 80 in this manner is inserted into the top case 2, and then secured to it by means of an engaging member.
As described above, the liquid crystal display module 1 includes the liquid crystal display panel 80, the plastic frame 82 and the top case 2, etc. The PCB 4 is very liable to be damaged by a static electricity generated from the attached driving circuitry and the interior of the liquid crystal display module 1. Accordingly, a ground part is provided at the top case 2, as shown in FIG. 2A and FIG. 2B, in order to protect the PCB 4 from a static electricity.
FIG. 2A and FIG. 2B are a detailed section view and a side view representing a ground part A of the liquid crystal display module 1 shown in FIG. 1, respectively.
Referring to FIG. 2A and FIG. 2B, the ground part of the conventional liquid crystal display module 1 includes a PCB 4 mounted with a driving circuitry for applying a driving signal to a liquid crystal display panel, a top case 2 that takes the form of bracket and is provided with a ground part for preventing the PCB 4 from a static electricity, and a plate 3 installed at the inside of the top case 2 to contact the PCB 4 with the ground part of the top case 2.
The PCB 4 is mounted with a driving circuitry for applying a data signal and a scanning signal, etc. to the liquid crystal display panel (not shown). The top case 2 plays a role to enclose the edge of the liquid crystal display panel. Also, the top case 2 is provided with a ground part as shown in FIG. 3A for preventing the PCB 4 from a static electricity generated upon assembly of circuit components or a static electricity generated at the interior of the system.
Referring to FIG. 3A, the top case 2 consists of a horizontal plane part 18 and a vertical plane part 19 bent vertically from the horizontal plane part 18. The inside of the vertical plane part 19 is provided with a copper film 12, that is, a grounding part connected to a ground terminal (not shown). The plate 3 takes a shape as shown in FIG. 3B so as to contact the PCB 4 with the copper film 12 of the top case 2.
Referring to FIG. 3B, the plate 3 includes a horizontal plane part 11 on which the PCB 4 is put, and a vertical supporting member 23 extended vertically and bent from one side thereof.
The horizontal plane part 11 is provided with a first screw hole 14 for fixing the PCB 4. The vertical supporting member 23 is provided with at least one protrusion 10 to be in contact with the copper film 12 of the top case 2. The plastic frame 82 in FIG. 1 is inserted between the horizontal plane part 11 and the vertical supporting member 23.
A static electricity generated from the driving circuitry mounted onto the PCB 4 contacts the copper film 12 of the top case 2 via the protrusion 10 provided at the vertical supporting member 23 of the plate 3 to flow into a ground terminal. In other words, the PCB 4 is in contact with the copper film 12 of the top case 2 via the plate 3 and grounded, thereby protecting the PCB 4 from a static electricity. This will be described in detail with reference to FIG. 4A and FIG. 4B.
FIG. 4A is a section view taken along the line B-Bxe2x80x2 line in FIG. 2A, and FIG. 4B is a section view taken along the line C-Cxe2x80x2 line FIG. 2B.
Referring to FIG. 4A and FIG. 4B, the PCB 4 becomes in contact with the plate 3 and fixed by passing a first screw 17 through a hole (not shown) defined on the PCB 4 and through a first screw hole 14 of the plate 3 and then inserting it into a first screw hole 16 formed at the plastic frame 82.
The plate 3 is fixed by passing a second screw (not shown) through a second screw hole (not shown) defined at the plate 3 and then inserting it into a second screw hole (not shown) defined at the plastic frame 82. The outer side of the plate 3 is covered with the top case 2. Accordingly, the protrusion 10 formed at the plate 3 is in contact with the copper film 12 formed at the inside of the top case 2. As a result, the PCB 4 is earthed to the copper film 12 via the plate 3, to thereby be protected from a static electricity generated upon assembly work and a static electricity generated from the interior of the system.
Further, the top case 2 covers the outer side of the PCB 4 and the plate 3, etc. by engaging a third screw 28 to the plastic frame 82 through a third screw hole 26 shown in FIG. 2A and FIG. 2B. At this time, the top case 2 raises a problem in that it is widened toward the outside thereof by X as shown in FIG. 5 when an engaging force of the third screw 28 is excessively strong.
This problem makes a grounding of the PCB 4 into the top case 2 impossible. Accordingly, the drivers (not shown) mounted onto the PCB 4 are damaged by a static electricity generated upon assembly work or a static electricity generated from the internal system. As a result, there occurs a problem in that a picture fails to be displayed on the liquid crystal display panel 80 due to such a damage of the drivers mounted onto the PCB 4.
Accordingly, it is an object of the present invention to provide a liquid crystal display module that is adaptive for improving a ground connection between a printed circuit board and a ground plate.
In order to achieve these and other objects of the invention, a liquid crystal display module according to an embodiment of the present invention includes a printed circuit board for applying signals to a liquid crystal display panel; a top case provided with a horizontal plane part and a vertical plane part bent vertically from the horizontal plane part to enclose the edge of the liquid crystal display panel; and a ground plate provided with an outer vertical supporting member being in contact with the outside of the vertical plane part of the top case to earth the printed circuit board.
In the liquid crystal display module, the top case includes a concave portion that is concavely defined at one side of the vertical plane part to be in contact with the outer vertical supporting member. The ground plate includes an inner vertical supporting member formed vertically to be in contact with the inside of the vertical plane part of the top case.
Further, the outer vertical supporting member has at least one protrusion being in contact with the concave portion of the top case and the inner vertical supporting member has at least one protrusion being in contact with the vertical plane part of the top case.
In the liquid crystal display module, the ground plate is made from an electrical-conductive material. The ground plate is a copper film.
A liquid crystal display module according to another aspect of the present invention includes a printed circuit board for applying signals to a liquid crystal display panel; a top case provided with a horizontal plane part and a vertical plane part bent vertically from the horizontal plane part to enclose the edge of the liquid crystal display panel; a ground plate provided with an outer vertical supporting member being in contact with the outside of the vertical plane part of the top case to earth the printed circuit board; and a plastic frame for supporting the ground plate.
In the liquid crystal display module, the top case includes a concave portion that is concavely defined at one side of the vertical plane part to be in contact with the outer vertical supporting member. The ground plate includes an inner vertical supporting member formed vertically to be in contact with the inside of the vertical plane part of the top case.
Further, the outer vertical supporting member has at least one protrusion being in contact with the concave portion of the top case and the inner vertical supporting member has at least one protrusion being in contact with the vertical plane part of the top case.
In the liquid crystal display module, the ground plate is made from an electrical-conductive material. The ground plate is a copper film.